Combi boiler v conventional

[3sonsequalschaos]

Thinking of renovating the kitchen and ditching the conventional boiler as the water tank takes a lot of space. We have a three storey, four bed two bathroom house. We've got very good water pressure. Anyone got any experience of Combi boilers pros and cons?

You’re probably just about on the upper limits of what a combi can deliver (we lived in a similar size house with a combi and it was fine, but obviously not possible to have two showers running etc). In this house we have a conventional boiler with an unvented cylinder which I think is my preferred setup now. I’m sure @PigletJohn could give you some excellent advice.

I am having a new boiler fitted and was told when they came out to do the survey that my house was too big for a combi.
I have 3 bathrooms with pumped showers, five beds and 5 adults living here and was advised to stick with a traditional boiler as the combi would struggle to provide enough hot water.
So I am going for a 25 watt condensing boiler which is more powerful than my 30 year old potterton.

We had a combi growing up and I thought it was great - we never ran out of hot water. I know live in a larger home with three bathrooms and we were told a combi wouldn’t be big enough - we have occasionally run out of hot water if we both shower once the timer has clicked off and it really winds me up!

Combi brilliant in a smaller house with one bathroom. Bigger than that an invented cylinder system. We can run 3 mains pressure showers off ours on 3 floors and live at the top of a huge hill.

RandomMess

I wonder how many litres per minute your combi can deliver

and, therefore, what a third of that is, when shared between your three showers.

edit

sorry, i misunderstood.

@3sonsequalschaos

measure the incoming water flow, which is not the same as pressure. A combi can usually deliver around 12 litres per minute of hot water (less in winter), which is enough for one good shower but meagre for two, and takes a long time to fill a bath.

Thanks

Very helpful thank you

I'm going to get someone in for advice but thanks very helpful. The water tank takes up so much room and racking my brain what to do

Yes this happens here too. The water tank is huge though so trying to weigh up what to do

Mmm. Food for thought

Do you have any loft space? If you changed the hot water tank to an unvented Megaflow type cylinder perhaps it could be put there and free space?

I understand that you could then loose the water supply tank as the mains cold water is directly connected to the hot tank.

The only reason I didn't do this is because we e showers and I like that they are all pumped and push out water under high pressure. Apparently can't have a water pump with this set up.

We have a 4 bed house with 3 showers and one bath and have a combi boiler.

Advantages are that hot water is available at any time, you can spend as long as you like in the shower without running out of hot water and there aren't water tanks taking up space in the house. Also no risk of a water tank leaking or bursting.

Disadvantages are that only one shower can be run at any one time and you can't have a pumped shower. There is also no alternative way to heat up water (e.g. immersion heater in hot water tank) should the boiler break down.

We find that running a hot tap will affect the shower. If we run 2 hot taps at the same time we get reduced pressure in each but that is not as inconvenient as a shower being affected. Running a cold tap or even flushing the loo will also give you a cold blast if you are in the shower at the time.

We are a household of 3 adults and 2 teens. We generally shower at different times of the day and will announce that we are about to take a shower so the other members of the household can refrain from running water for the duration of the shower. I expect we have evolved this system due to the fact that we have a combi boiler but to me this is a minor inconvenience.

I grew up in a household of 7 and we had a water tank which was always running out of hot water. Of course, that could have been because the tank was too small or my parents didn't heat it up often enough, but I love being able to shower or fill up the sink with no fear of running out of hot water.

For a one bathroom property combi’s are best. It might still work well for you with two bathrooms. Just remember that two showers running, filling up the kitchen sink, with the dishwasher and washing machine filling up will leave you standing under a dribble.
So the question to ask yourself is how often, will multiple outlets be running simultaneously, and then decide if ur happy with that compromise v’s waiting for a hot water tank to heat up on the occasions that it runs out or was off.
I think if I was going to be taking a shower every day at exactly the same time as another family member, then that might be enough to persuade me to go with a tanked system. If you go tanked, you then need to decide sealed or vented, and a sealed one still may have issues with two showers simultaneously, however I have no experience on that front.

I don't know about "best" but they are acceptable.

With luck they will not go wrong very often, leaving you with no hot water.

When a combi fails, it is an emergency.

When a conventional fails (less often) you turn on the electric and try to remember to get it fixed before next winter.

We tend to take showers at different times so this is helpful. Our loft is converted so can't do anything up there. The amount of pipes and stuff attached to the tank is mind boggling and takes up so much space I want to use for storage that I like the idea of the Combi. Have to convince the husband about the additional cost of a new boiler and sorting out decades old labyrinth of pipes for a nice new kitchen.

Very rarely a
More than one using the shower at once. Three boys who tend to avoid personal cleanliness unless prompted!

If you go with the combi then get a thermostatic controlled shower fitted so if someone runs a tap etc you don't get scalded or frozen, the pressure drops but the temperature stays static.

We have 2 bathrooms and a combi, I agree running 2 showers off a combi will decrease the flow/performance of the shower.

To over come this we put an electric shower in one of them , it still slows the flow down a bit but not too noticeable ( we have strong mains water pressure ) and also if the boiler conks out we still have hot showers .

Some people don’t like the pressure an electric shower gives but I don’t mind , our thermostatic showers toopowerful and makes my skin sting.

@RandomMess

If you go with the combi then get a thermostatic controlled shower fitted so if someone runs a tap etc you don't get scalded or frozen, the pressure drops but the temperature stays static.

Yes, thermostatic is the way to go. In my second house with a combi, but both places are/were relatively small, just one main bathroom. In the previous house, I was always blasted with freezing water if DH decided to wash his tea cup in the kitchen while I was showering. So made sure to install thermostatic shower during a recent bathroom refurb in our "new" house. As RandomMess says, if there's another demand on water supply, the pressure in the shower drops, but the temperature remains comfortable. Plus, we've gone for a higher capacity combi (30kw), so the pressure drop is not that bad. When we planned the boiler replacement, we talked to an engineer about alternatives, as we're thinking about adding an en-suite shower in the future. He said that no combi would cope with two showers running simultaneously, but we think/hope we wouldn't use both at the same time, and the space was at premium, so went for a combi in the end.